Store procedure to take Back up operation of certain column values.

Question

Hi ,
Can anyone please tell me how to do this?
I have three table 1:emp(empno,ename,deptno,sal)
2:emp_changes(empno,changetime(timestamp),operation(varchar2))
3:emp_metadata(tablename(varchar),Maxtime(timestamp))
I want to create a trigger which will track all the DML operation on emp table and insert one row for each operation having empno(as primary in emp) ,timstamp of operation and operation name (Insert,update or delete) in emp_changes table.
As well as it will insert or update in emp_metadata table with name of the table and max time from emp_changes table.
emp_changes table will have only one row.if there is no row it will insert otherwise it will update that row.
can anone please write this trigger for me?
Thanks,
Deekay.
Edited by: Deekay on Aug 9, 2010 4:15 AM

Answer 1

Try this:
SQL> create table emp(empno number,ename varchar2(10),sal number);
Table created.
SQL> create table emp_Change(empno number,changetime timestamp,operation varchar2(10));
Table created.
SQL> create table emp_metadata(tablename varchar2(1000),maxtime timestamp);
Table created.
SQL> create or replace trigger my_emp_trig after insert or update or delete on emp
  2  for each row
  3  begin
  4  IF INSERTING THEN
  5  /
Warning: Trigger created with compilation errors.
SQL> ed
Wrote file afiedt.buf
  1  create or replace trigger my_emp_trig after insert or update or delete on emp
  2  for each row
  3  v_empno NUMBER := 0;
  4  begin
  5  BEGIN
  6  SELECT empno INTO v_empno FROM emp_Change where empno = :new.empno;
  7  exception
  8  when no_Data_found then
  9  v_empno := 0;
10  end;
11  IF (v_empno = 0) THEN
12  IF INSERTING THEN
13  insert into emp_change values(:new.empno,SYSTIMESTAMP,'INSERT');
14  ELSIF UPDATING THEN
15  insert into emp_change values(:new.empno,SYSTIMESTAMP,'UPDATE');
16  ELSE
17  insert into emp_change values(:new.empno,SYSTIMESTAMP,'DELETE');
18  END IF;
19  ELSE
20  IF INSERTING THEN
21  update emp_change set operation='INSERT',changetime=SYSTIMESTAMP
22  WHERE empno = :new.empno;
23  ELSIF UPDATING THEN
24  update emp_change set operation='UPDATE',changetime=SYSTIMESTAMP
25  WHERE empno = :new.empno;
26  ELSE
27  update emp_change set operation='DELETE',changetime=SYSTIMESTAMP
28  WHERE empno = :new.empno;
29  END IF;
30  END IF;
31* end;
32  /
v_empno NUMBER := 0;
ERROR at line 3:
ORA-04079: invalid trigger specification
SQL> ed
Wrote file afiedt.buf
  1  create or replace trigger my_emp_trig after insert or update or delete on emp
  2  for each row
  3  declare
  4  v_empno NUMBER := 0;
  5  begin
  6  BEGIN
  7  SELECT empno INTO v_empno FROM emp_Change where empno = :new.empno;
  8  exception
  9  when no_Data_found then
10  v_empno := 0;
11  end;
12  IF (v_empno = 0) THEN
13  IF INSERTING THEN
14  insert into emp_change values(:new.empno,SYSTIMESTAMP,'INSERT');
15  ELSIF UPDATING THEN
16  insert into emp_change values(:new.empno,SYSTIMESTAMP,'UPDATE');
17  ELSE
18  insert into emp_change values(:new.empno,SYSTIMESTAMP,'DELETE');
19  END IF;
20  ELSE
21  IF INSERTING THEN
22  update emp_change set operation='INSERT',changetime=SYSTIMESTAMP
23  WHERE empno = :new.empno;
24  ELSIF UPDATING THEN
25  update emp_change set operation='UPDATE',changetime=SYSTIMESTAMP
26  WHERE empno = :new.empno;
27  ELSE
28  update emp_change set operation='DELETE',changetime=SYSTIMESTAMP
29  WHERE empno = :new.empno;
30  END IF;
31  END IF;
32* end;
SQL> /
Trigger created.
SQL> insert into emp values(1,'A',10000);
1 row created.
SQL> commit;
Commit complete.
SQL> select * from emp;
     EMPNO ENAME             SAL
         1 A               10000
SQL> select * from emp_change;
     EMPNO
CHANGETIME
OPERATION
         1
06-AUG-10 06.42.37.309898 AM
INSERT
SQL> update emp set sal=200000 where empno = 1;
1 row updated.
SQL> commit;
Commit complete.
SQL> set linesize 10000
SQL> select * from emp_change;
     EMPNO CHANGETIME                                                                  OPERATION
         1 06-AUG-10 06.43.05.368925 AM                                                UPDATE
SQL> insert into emp values(2,'B',123456);
1 row created.
SQL> commit;
Commit complete.
SQL> select * from emp;
     EMPNO ENAME             SAL
         1 A              200000
         2 B              123456
SQL> select * from emp_change;
     EMPNO CHANGETIME                                                                  OPERATION
         1 06-AUG-10 06.43.05.368925 AM                                                UPDATE
         2 06-AUG-10 06.43.29.383845 AM                                                INSERTSimilarly you can tryout for emp_metadata